REFILE-US' Dempsey says premature to attack Iran now

(Fixes preposition in paragraph 4)

* Dempsey thinks Iranian government "rational actor"

* Won't say that Israelis have been persuaded against attack

WASHINGTON, Feb 19 (Reuters) - The top U.S. military
officer said on Sunday that a military strike against Iran would
be premature, because it is unclear that Tehran will actually
use its nuclear capabilities to build an atomic bomb.

There has been public discussion in Israel about whether it
should attack Iran to stop it from developing a nuclear bomb.

The two foes have traded blame over incidents that ratcheted
up tensions recently: Israeli diplomats were attacked abroad and
an Iranian nuclear scientist was assassinated in Tehran.

But General Martin Dempsey, chairman of the U.S. military's
Joint Chiefs of Staff, said he believed the Iranian government
was a "rational actor." Therefore, it was best for the United
States and its allies to stick with international sanctions and
diplomacy to try to convince Tehran not to weaponize its nuclear
program, Dempsey told CNN's "Fareed Zakaria GPS."

"I believe it is unclear (that Iran would assemble a bomb)
and on that basis, I think it would be premature to exclusively
decide that the time for a military option was upon us," Dempsey
said.

He said he was confident Israel knew that this was the
general U.S. attitude, but he stopped short of suggesting that
the Americans had persuaded the Israelis that it was best not to
attack Iran.

"I'm confident that they (Israel) understand our concerns
that a strike at this time would be destabilizing and wouldn't
achieve their long-term objectives," he said.

Iranian leaders have responded sharply to speculation that
Israel could bomb Iran within months to stop it from assembling
nuclear weapons, threatening to retaliate against any country
that launches an attack against the Islamic Republic.

Israel, which is widely believed to have the only nuclear
arsenal in the Middle East, says a nuclear-armed Iran would
threaten its existence. Iran says its nuclear program is for
peaceful purposes.

But Iran's recent shift of uranium enrichment to a mountain
bunker - possibly impervious to conventional bombing - and
refusal to negotiate peaceful guarantees for the nuclear program
have raised fears about Iran's ambitions as well as concerns
about Gulf oil supplies.

However, U.S. and European officials on Friday voiced
cautious optimism over the latest signals from Tehran that it
might be willing to resume talks with major powers on the
nuclear issue, after the Iranians sent them a letter.

The United States also has not ruled out the use of military
force to stop Iran getting a bomb. Dempsey said the U.S.
military had to have options available "should the nation decide
to do something in Iran".

"I mean, fundamentally, we have to be prepared," he said.
"And that includes, for the most part, at this point, being
prepared defensively."

Dempsey discussed Iran with Israeli leaders during a visit
there last month. His interview was aired on CNN as President
Barack Obama's national security adviser, Tom Donilon, was on a
visit to Israel for talks on regional issues including Syria and
Iran.

Lieutenant General Ronald Burgess, director of the U.S.
Defense Intelligence Agency, said on Thursday U.S. agencies
believed Israel had not yet taken a decision to launch a
full-scale military strike on Iranian nuclear sites.